Role of Multidetector Computed Tomography in the Assessment of Olfactory Fossa Depth among the South Indian Population: A Cross-sectional Study

Introduction: Functional Endoscopic Sinus Surgery (FESS) is one of the most commonly performed surgeries for sinusitis. The olfactory fossa is prone to injury during FESS and the risk of injury depends on the depth of the olfactory fossa. Aim: To assess the depth of the olfactory fossa by multidetector Computed Tomography (CT) and to study the incidence and distribution of asymmetry of olfactory fossa depth. Materials and Methods: A cross-sectional, observational study was conducted at Department of Radiology, Dr Pinnamaneni Siddhartha Institute of Medical Sciences and Research Foundation, Gannavaram, Andhra Pradesh, India from November 2019 to October 2019. The sample size was 500 patients. All patients above the age of 18 years who were referred to the department of radiology for CT paranasal sinuses were included. Olfactory fossa depth was calculated from the CT scan and statistical analysis was done comparing it with the variables such as age, gender and side of fossa. Results: Out of total 500 participants, 311 (74.2%) patients in the study were males. The mean age of patients was 40.3±16.05 years. There was no significant difference in the olfactory fossa depth on the right side (p-value=0.6) and left side (p-value=0.9) in both genders. A total of 400 (80%) patients of the cases had asymmetry of the olfactory fossa. In males, the most common (n=294, 799.2%) was type 2 Keros on the right and 280 (75.5%) patients on the left side. In females on the right side, type 1 Keros was more common (52 patients, 40.3%) and on the left side type 2 Keros was more common (60 patients, 46.5%) and there was a significant difference in the proportion of different types of Keros in both genders (p-value<0.001). There was no significant difference in the proportion of Keros types among the different age groups (p-value=0.56 on the right side and p-value=0.66 on left side). Conclusion: There was a significant difference in the proportion of Keros types among males and females and the majority of the patients had asymmetry. Prospective studies with intraoperative information from the surgeon can add further information on the utility of the Keros grade.